UMMS Affiliation

Department of Molecular, Cell and Cancer Biology; Department of Biochemistry and Molecular Pharmacology; UMass Metabolic Network

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Biochemistry | Biology | Cell Biology | Cellular and Molecular Physiology | Molecular Biology


The repeating subunit of chromatin, the nucleosome, includes two copies of each of the four core histones, and several recent studies have reported that asymmetrically-modified nucleosomes occur at regulatory elements in vivo. To probe the mechanisms by which histone modifications are read out, we designed an obligate pair of H3 heterodimers, termed H3X and H3Y, which we extensively validated genetically and biochemically. Comparing the effects of asymmetric histone tail point mutants with those of symmetric double mutants revealed that a single methylated H3K36 per nucleosome was sufficient to silence cryptic transcription in vivo. We also demonstrate the utility of this system for analysis of histone modification crosstalk, using mass spectrometry to separately identify modifications on each H3 molecule within asymmetric nucleosomes. The ability to generate asymmetric nucleosomes in vivo and in vitro provides a powerful and generalizable tool to probe the mechanisms by which H3 tails are read out by effector proteins in the cell.


S. cerevisiae, chromatin, chromosomes, genes, synthetic biology, transcription

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Copyright © 2017, Ichikawa et al.

DOI of Published Version



Elife. 2017 Sep 12;6. doi: 10.7554/eLife.28836. Link to article on publisher's site

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Full list of authors omitted for brevity. For full list see article.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.